1. Field of the Invention
The present invention relates to a hybrid integrated circuit device, and more particularly to a light irradiation device in which a plurality of light emitting elements are mounted.
2. Description of the Related Art
When a plant such as a flower or a vegetable is to be irradiated with a large amount of light, a device such as an electric lamp is usually used. In some cases, in order to reduce the size and weight of the device and the power consumption, a device in which light emitting elements 2 are mounted on a printed circuit board 1 as shown in FIG. 15 is used.
As the light emitting elements, light emitting diodes which are configured by semiconductor materials are mainly used. Alternatively, semiconductor lasers or the like may be used.
In each of the light emitting diode chips 2, two leads 3 and 4 are used. The rear face (anode or cathode) of the light emitting diode chip 2 is fixed to the lead 3 by soldering or the like. The other lead 4 is electrically connected via a thin metal wire 6 to an electrode (cathode or anode) on the surface of the chip. A transparent resin sealing member 7 which will serve as a lens is formed to seal the leads 3 and 4, a bare diode 5, and the thin metal wire 6.
On the other hand, electrodes 8 and 9 for supplying a power to the light emitting diode 2 are disposed on the printed circuit board 1. The leads are inserted into through holes opened in the electrodes. The light emitting diode 2 is mounted on the board via solder or the like.
A light irradiation device using such light emitting diodes is described in, for example, JP-A-9-252651.
As described above, the light emitting element 2 is configured by a package into which the resin sealing member 7, the leads 3 and 4, and the like are incorporated. When a large number of light emitting elements are mounted, therefore, there arise problems such as that the circuit board 1 is large in size and weight. Since the heat radiation properties of the circuit board itself are inferior, the circuit board has a problem in that the temperature of the whole device is excessively raised. Consequently, the temperatures of semiconductor chips themselves which constitute the light emitting elements are raised, thereby producing a problem in that the driving ability is lowered.
In the light emitting diode 2, light is emitted also from side and rear faces, and hence light directed toward the circuit board 1 exists. Since the circuit board 1 is configured by a printed circuit board, there is another problem in that irradiation of a high efficiency cannot be realized.
The invention has been conducted in view of the above-discussed problems, and the present invention intends to obtain a light irradiating apparatus which can obtain an efficient light.
The present invention solves the problems by disposition of first flow-stopping means which is formed to substantially surround a light emitting element, and which is made of a brazing material, and a light transmitting resin which is protrudingly formed in a region surrounded by the first flow-stopping means.
The light transmitting resin before curing is held to a protruding shape by the flow-stopping means, and then cured. Therefore, the resin exhibits also a lens function. Since the flow-stopping means is configured by a brazing material, light emitted from the light emitting element can be efficiently upward reflected by using the glossiness of the surface of the brazing material and the protruding shape of the brazing material. As a result, irradiation of a high efficiency can be realized.
A brazing material is electrically conductive. When a brazing material is formed so as to be continuous over the whole periphery, therefore, a short circuit occurs. This problem is solved by disposing second flow-stopping means which is made of an insulating material, in a portion of the brazing material, the portion overlapping with the first electrode and/or the second electrode.
The problems are solved by a configuration in which first and second electrodes made of Cu are employed, first flow-stopping means which is formed around a light emitting element, and a protruding light transmitting resin are disposed,
a metal film covers the first electrode and/or said second electrode, the metal film being inferior in wettability with respect to a brazing material and superior in light reflection than the Cu,
a portion of the metal film corresponding to the first electrode and/or said second electrode and in a region where the first flow-stopping means is disposed is removed away, and a brazing material is formed in the region.
With respect to solder, for example, Ni is inferior in wettability than Cu. Furthermore, Ni maintains glossiness of the surface for a long term. Solder also maintains glossiness of the surface for a long term. These properties are used in the invention. Specifically, a Cu film is formed as a lower layer, an Ni film is formed as an upper layer, and a part of the Ni film is removed away to form a Cu exposed region. When solder is formed in the exposed region, the resulting solder upward protrudes. The protruding solder surface forms a reflective plate to efficiently upward reflect light which cannot be upward reflected in the conventional art.
As seen from the above description, when a substrate mainly made of Al is employed, particularly, it is possible to realize a hybrid integrated circuit device which can attain excellent heat radiation properties, light weight, and high workability, and which has a high reflection efficiency.
Each aspect if the device described below is separately illustrative of the various embodiments of the invention and is not intended to be restrictive of the broad invention.
Namely, a first aspect of the device is a hybrid integrated circuit device comprising:
first and second electrodes formed on a substrate;
a light emitting element in which a rear face of a chip is electrically fixed to said first electrode;
connecting means for electrically connecting said second electrode to an electrode which is on a surface of said light emitting element;
first flow-stopping means which is formed to substantially surround said light emitting element, and which is made of a brazing material; and
a which is protrudingly formed in a region surrounded by said first flow-stopping means.
A second aspect of the device is a hybrid integrated circuit device according to the first aspect, wherein said flow-stopping means is a ring made of an insulating resin.
A third aspect of the device is a hybrid integrated circuit device according to the first aspect, wherein the flow-stopping means comprises a first flow-stopping means made of a brazing material and a second flow-stopping means made of an insulating material is disposed in a portion of said brazing material, said portion overlapping with said first electrode and/or said second electrode.
A fourth aspect of the device is a hybrid integrated circuit device according to the third aspect, wherein the second flow-stopping means is made of epoxy resin, and the light transmitting resin is made of silicone resin.
A fifth aspect of the device is a hybrid integrated circuit device according to the first aspect, wherein the first and second electrodes are made of reflective material.
A sixth aspect of the device is a hybrid integrated circuit device according to the first aspect, wherein the first and second electrodes are made of nickel.
A seventh aspect of the device is a hybrid integrated circuit device according to the first aspect, further comprising a solder resist layer formed so as to cover the first and second electrodes.
An eighth aspect of the device is a hybrid integrated circuit device according to the first aspect, wherein said substrate is made of a metal substrate whose surface is insulative processed.
A ninth aspect of the device is a hybrid integrated circuit device according to the first aspect, wherein the device comprises:
a wiring portion consisting of a first wiring of reflective conductive film so as to cover an whole surface of a substrate; and a second wiring facing to the first wiring through a slit;
a light emitting element mounting region formed on a part of the wiring portion comprising the first wiring and the second wiring connected with the first and second electrodes respectively; and
a light emitting element mounted on the first and second electrode so as to introduce a light emitted by the light emitting elements into a front direction effectively.
A tenth aspect of the device is a hybrid integrated circuit device according to the first aspect, wherein said hybrid integrated circuit device comprises:
first and second electrodes which are insulatedly formed on a hybrid integrated circuit substrate, and which are made of Cu;
a light emitting element in which a rear face of a chip is electrically fixed to said first electrode;
connecting means for electrically connecting said second electrode to an electrode which is on a surface of said light emitting element;
first flow-stopping means which is formed around said light emitting element; and
a light transmitting resin which is protrudingly formed in a region surrounded by said first flow-stopping means,
a metal film covers said first electrode and/or said second electrode, said metal film being inferior in wettability with respect to a brazing material and superior in light reflection than the Cu,
a portion of said metal film corresponding to said first electrode and/or said second electrode and in a region where said first flow-stopping means is disposed is removed away, and a brazing material is formed in said region.
An eleventh aspect of the device is a hybrid integrated circuit device according to the third aspect, wherein said first electrode is formed in an annular shape to substantially surround said second electrode, and said brazing material is formed on said first electrode in a substantially annular shape.
A twelfth aspect of the device is a hybrid integrated circuit device according to the third aspect, wherein said first electrode is formed in an annular shape to substantially surround said second electrode, and said region where said brazing material is formed is formed in a substantially island-like shape in said first electrode.
A thirteenth aspect of the device is a hybrid integrated circuit device according to the third aspect, wherein said metal film is made of Ni.
A fourteenth aspect of the device is a hybrid integrated circuit device according to the first aspect, wherein a plurality of said light emitting elements are connected in series on said hybrid integrated circuit substrate.
A fifteenth aspect of the device is a hybrid integrated circuit device according to the first aspect, wherein the light transmitting resin has a two stage structure so as to introduce a light emitted by the light emitting elements into a front direction effectively.